docs: def load(filename, to_replace=dict()):
      ''' Load NIDM-Results file given filename, guessing if it is a
      NIDM-Results pack or a JSON file
  
      Parameters
      ----------
      filename : string
         specification of file to load
      Returns
      -------
      nidmres : ``NIDMResults``
         NIDM-Results object
      '''
      if not os.path.exists(filename):
          raise IOException('File does not exist: %s' % filename)
  
      if filename.endswith('.json'):
          raise Exception('Minimal json file: not handled yet')
      elif filename.endswith('.nidm.zip'):
          nidm = NIDMResults.load_from_pack(filename, to_replace=to_replace)
      else:
          raise Exception('Unhandled format ' + filename)
  
      return nidm